The present invention relates to a beam monitor system for monitoring the beam position in a charged particle beam (particle beam) irradiation system. In particular, the present invention relates to a beam monitor system for a particle beam irradiation system that can be suitably employed for a particle therapy system for treating affected parts (infected parts) by irradiating the affected parts with a particle beam of protons, carbon ions, etc.
There is a well-known method of treating cancer patients, etc. by irradiating an affected part in the patient's body with a charged particle beam (particle beam, ion beam) such as a proton beam or a carbon ion beam. The particle beam irradiation system used for the treatment comprises a charged particle beam generator. The ion beam accelerated by the charged particle beam generator reaches an irradiation device (irradiation nozzle) installed in a rotating gantry via a first beam transport line and a second beam transport line which is arranged in the rotating gantry. The ion beam is emitted from the irradiation device and applied to the affected part in the patient.
Various known irradiation methods can be employed by the irradiation device (see Review of Scientific Instruments, Volume 64, Number 8 (August 1993), Pages 2074-2093, for example). Such irradiation methods include the double scattering method in which the beam is broadened by use of a scatterer and then cut out in conformity with the shape of the affected part (see page 2081 and FIG. 35 of the above literature), the wobbler method (see page 2084 and FIG. 41 of the above literature), and the scanning method in which a thin beam is scanned within the target area (see pages 2092 and 2093 of the above literature).